Try the Library of Congress' Chronicling America (it carries that newspaper) https://chroniclingamerica.loc.gov/lccn/sn82016187/I'm wondering if there is a file of the National Tribune newspapers in the National Archives in Washington.
Grandfather wrote several articles and letters for the Tribune and on occasion received letters from veterans.
He had just completed his first year at Moores Hill Male and Female College in the spring of 1861.
The 7th Indiana was one of the first six regiments organized for three months (in deference to the five who
served in the Mexican War). Grandfather turned 18 in June 1861 and enlisted at the blacksmith's shop.
He survived two wounds and served for three years. He later became an lawyer and judge in Grayson, KY.
I have the original letters written by the veterans along with his history of the 7th Indiana Infantry Regiment.